Ariadna Zybek-Kocik

Time-dependent irisin concentration changes in patients affected by overt hypothyroidism.

INTRODUCTION Irisin, a cleaved and secreted part of the transmembrane protein FNDC5, is a recently discovered adipo-myokine that is said to have a significant influence on body metabolism. Changes in thyrometabolic state may also alter the serum irisin level. Since already reported data are not fully consistent, the aim of the present research is to evaluate the time-dependent changes in serum irisin level in patients affected by overt hypothyroidism. MATERIAL AND METHODS The study involved 36 subjects - two groups of 12 patients with long-lasting (AITD) and short-term (TC) overt hypothyroidism, and a control group (CG) of 12 subjects, matched for age and gender. Serum irisin level, thyrometabolic state, creatine kinase (CK - muscle damage marker), glucose, and insulin concentration were assessed and compared between groups. RESULTS The irisin level was significantly lower in AITD than in TC and CG (p = 0.02; p < 0.01; respectively) patients, with no statistical difference between TC and CG (p > 0.05). There was no significant difference between free triiodothyronine and free thyroxine levels in AITD and TC patients (p > 0.05). CK concentration was significantly higher in AITD than in CG patients (p < 0.01) with no difference between AITD and TC patients (p > 0.05) as well as TC and CG patients (p > 0.05). Additionally, the CK level negatively correlated with the irisin level (r = -0.58; p < 0.01). CONCLUSIONS In conclusion, the irisin concentration changes during thyroid function impairment may be time-dependent. Patients with prolonged hypothyroidism have lower irisin levels that those with short-term disorder. (Endokrynol Pol 2016; 67 (5): 476-480).

The association between irisin and muscle metabolism in different thyroid disorders

Irisin is a new adipo‐myokine, encoded by the FNDC5 gene. Currently, there is a discussion regarding the relation between thyroid function and irisin concentration. This prospective study assesses the influence of thyrometabolic changes on serum irisin concentration in association with altered muscle metabolism. This is performed on a large cohort of patients affected by severe hypo‐ or hyperthyroidism, as well as by the expression of the FNDC5 gene in thyroid tissue affected by different pathologies.

Circulating Visfatin in Hypothyroidism Is Associated with Free Thyroid Hormones and Antithyroperoxidase Antibodies

We hypothesized that regulation of visfatin in hypothyroidism might be altered by coexisting chronic autoimmune thyroiditis. This is a prospective case-control study of 118 subjects. The autoimmune study group (AIT) consisted of 39 patients newly diagnosed with hypothyroidism in a course of chronic autoimmune thyroiditis. The nonautoimmune study group (TT) consisted of 40 patients thyroidectomized due to the differentiated thyroid cancer staged pT1. The control group comprised 39 healthy volunteers adjusted for age, sex, and BMI with normal thyroid function and negative thyroid antibodies. Exclusion criteria consisted of other autoimmune diseases, active neoplastic disease, diabetes mellitus, and infection, which were reported to alter visfatin level. Fasting blood samples were taken for visfatin, TSH, free thyroxine (FT4), free triiodothyronine (FT3), antithyroperoxidase antibodies (TPOAb), antithyroglobulin antibodies (TgAb), glucose, and insulin levels. The highest visfatin serum concentration was in AIT group, and healthy controls had visfatin level higher than TT (p = 0.0001). Simple linear regression analysis revealed that visfatin serum concentration was significantly associated with autoimmunity (β = 0.1014; p = 0.003), FT4 (β = 0.05412; p = 0.048), FT3 (β = 0.05242; p = 0.038), and TPOAb (β = 0.0002; p = 0.0025), and the relationships were further confirmed in the multivariate regression analysis.

Electrocardiographic and scintigraphic evaluation of patients with subclinical hyperthyroidism during workout

Subclinical hyperthyroidism (sHT) was found to be associated with elevated heart rate, blood pressure and increased risk of extrasystoles. However, the full clinical relevance of morphological and functional implications of sHT on the cardiovascular system is still a matter of debate. The aim of the study was to prospectively assess the influence of endogenous sHT on exercise capacity and cardiac function during workout with the use of exercise electrocardiography (ExECG) and perfusion scintigraphy. The studied group consisted of 44 consecutively recruited patients diagnosed with sHT. In all patients, ExECG, followed by post-exercise myocardial perfusion imaging, was performed. Both ExECG and scintigraphy were performed twice—in the state of sHT and after euthyroidism was restored. An average time period of exercise test was significantly longer in the state of euthyroidism than in sHT. An average oxygen consumption during exercise test was also higher after euthyroidism was achieved when compared to sHT. The end-diastolic and end-systolic volume indexes, stroke volume index and cardiac index were significantly larger in patients with sHT if compared values achieved after euthyroidism restoration. Stroke volume index was negatively correlated with TSH, and positively with free thyroid hormones values in the state of sHT, before euthyroidism was achieved. Cardiac index was positively correlated with free thyroid hormones levels. The obtained results indicate worse physical capacity in subjects with sHT and improvement of several parameters assessed during ExECG and perfusion scintiscan after therapy. Observed changes might reflect the mechanism of the deleterious effect exerted by sHT on the heart.

Thyroid hemiagenesis: incidence, clinical significance and genetic background.

Context: Thyroid hemiagenesis (THA) constitutes a rare, congenital disorder that is characterized by an absence of one thyroid lobe. Because the pathogenesis and clinical significance of this malformation remain undefined, specific clinical recommendations are lacking, especially for asymptomatic cases. Evidence Acquisition: The PubMed database was searched (years 1970 to 2017), and the following terms were used to retrieve the results: “thyroid hemiagenesis,” “thyroid hemiaplasia,” “one thyroid lobe agenesis,” and “one thyroid lobe aplasia.” Subsequently, reference sections of the retrieved articles were searched. Evidence Synthesis: There is a noticeable susceptibility of subjects with THA to develop additional thyroid and nonthyroidal pathologies. In pathogenesis of concomitant thyroid pathologies, a chronic elevation in thyroid‐stimulating hormone values may play an important role. Thus far, genetic studies failed to find a common genetic background of the anomaly, and the potential underlying cause was identified in a minority of the cases. Conclusions: Patients with THA are prone to develop additional thyroid pathologies and theoretically might benefit from L‐thyroxine treatment to lower the thyrotropin levels to those observed in the normal population. However, further research should be done to ascertain whether such intervention early in life would prevent development of associated thyroid conditions. At least, increased vigilance should be maintained to reveal all of the concomitant disorders as soon as possible during follow‐up examinations. Application of high‐throughput technologies enabling a genome‐wide search for novel factors involved in thyroid embryogenesis might be the next step to expand the knowledge on THA pathogenesis.

Red cell distribution width — a new marker for exacerbation of heart failure in patients with hypothyroidism following radioiodine therapy

INTRODUCTION Cardiovascular diseases constitute a major cause of health problems and death in developed countries across the world. The increased value of the index of distribution of red blood cells volume (RDW) may be a prognostic marker in patients diagnosed with chronic heart failure (CHF). Hypothyroid patients present higher RDW values if compared to healthy controls. Taking into consideration that RDW might be both affected by thyroid status and CHF, we decided to determine the effect of concomitant hypothyroidism following radioiodine therapy (RIT) and CHF on hematological parameters. MATERIALS AND METHODS Patients with toxic nodular goiter and heart failure with concomitant anemia were included. Patients underwent treatment with radioiodine before the planned heart transplant or pacemaker implantation (combined ICD/CRT-D). After RIT patients were divided into the three subgroups: with overt hypothyroidism (TSH ≥ 10µIU/mL, Group I), subclinically hypothyroid patients (TSH 4.3-9.0 µIU/mL, Group II) and with high-normal level of TSH (2.6-4.2 µIU/mL, Group III). RESULTS Significant correlation between TSH and RDW was observed (r=0.46; P < 0.0001) after RIT, whereas no correlation between serum TSH levels and TIBC and Fe was observed. In Group I significant correlation between TSH and RDW (r= 0.48; P = 0.002) after RIT was observed, whereas in two other subgroups there were no significant correlation. CONCLUSIONS Subclinical hypothyroidism or high-normal levels of TSH did not affect RDW in a significant manner in the studied population. Our results demonstrates that overt hypothyroidism may contribute to deterioration of CHF reflected in changes of RDW value. < p > < /p >.